1. Field of the Invention
The present invention relates to a photoelectric conversion apparatus, and more particularly, to a photoelectric conversion apparatus configured to detect a maximum value or a minimum value of signals output from a plurality of pixels.
2. Description of the Related Art
A photoelectric conversion apparatus is known that is used as an autofocus sensor (hereinafter referred to as an AF sensor) for a camera and that has a function of detecting a maximum value and a minimum value of signals output from a plurality of pixels. In a configuration in which all pixels in one row are connected to an output line via a voltage follower of each pixel, it is known to output the maximum value or the minimum value by simultaneously connecting all voltage followers in one row to the output line, as disclosed in Japanese Patent Laid-Open No. 2000-050164.
In the AF sensor, there is a need for higher performance of focusing operation in terms of accuracy and operation speed. To meet the need for higher accuracy of focus, there is a tendency to provide a greater number of pixels in the AF sensor. However, the increase in the number of pixels leads to an increase in the length of the output line and an increase in the number of elements connected to the output line. This results in an increase in parasitic impedance associated with the output line, which leads to an increase in time to charge and discharge the output line. Thus, a reduction occurs in response speed of signal output.